Because obesity is reaching epidemic proportions, results in marked morbidity and mortality, and is resistant to treatment, it is vital to develop prevention programs for this public health problem. Unfortunately, most universal prevention programs have not reduced the risk for future weight gain. Thus, we decided to target a subset of individuals-female restrained eaters entering college-who might be uniquely motivated to make lasting changes to their diet and activity level that would decrease their risk for obesity onset. In the proposed College Weight Control Program (CWCP), adolescent females are taught methods to reduce the portion size and energy density of their food choices and to increase their physical activity to prevent weight gain. The intervention utilizes persuasion principles from social and clinical psychology (e.g., strategic self-presentation, motivational interviewing) to increase the likelihood that participants will make lasting behavioral changes. The 5-session intervention is brief relative to extant programs, which should facilitate dissemination. A preliminary trial (N = 188) found that participants who completed an earlier version of this program were at significantly lower risk for obesity onset (3%) over a 2-year follow-up relative to assessment-only controls (11%) and showed greater improvements in healthy eating and activity level. This program also reduced eating disorder symptoms and negative affect, which is important because these disturbances are marked by functional impairment and adverse outcomes. Accordingly, we propose to conduct a large-scale randomized trial of an enhanced version of this targeted obesity prevention program at 2 local universities. We will randomly assign 350 female restrained eaters (aged 17-19) during their freshman year to the control or experimental group and follow them for 2 years. We will test whether the CWCP, relative to a no-treatment control condition, results in (1) decreased risk for gain of body fat and onset of obesity, (2) improvements in energy intake and the nutritional composition of the diet, (3) increases in physical activity, (4) decreased eating disorder and depressive symptoms, and (5) reduced levels of several medical risk factors.